More than 90 per cent of members of train drivers’ union Aslef had voted in favour of the industrial action last week.

Now union representative Finn Brennan has said a second strike on Wednesday, September 17, could be on the table. He added the union has heard nothing from TfL management since Friday.

Last week Mr Brennan said London Underground had refused “to treat drivers with the respect and dignity they deserve at work”.

“Our members will not tolerate a situation where vulnerable people leave sickness review meetings in tears and drivers with years and years of good and long service are threatened with disciplinary action for a delay of 33 seconds in leaving a terminus,” he said.

He also criticised LUL for cutting annual referesher training for Central line drivers.

Lance Ramsay, London Underground’s general manager, said: “We have been holding discussions with ASLEF to work through local issues they have raised within our agreed processes.

“Strike action is not necessary and we urge them to continue talks with us to understand and resolve their concerns.”